﻿//=============================================================
//  Copyright (C) 2017-2100
//  CLR版本:                    4.0.30319.42000
//  机器名称:                   YANGPENGFEIPC
//  命名空间名称/文件名:        YPF.Common.验证码_Drawing_/ValidateCode 
//  创建人:                     杨朋飞     
//  创建时间:                   2017/10/29 23:30:48
//  网站：                      http://www.jianshu.com/u/40fb2e2a8047
//  内容说明：ASP.NET MVC5 生成验证码
//==============================================================

using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.IO;

namespace YPF.Common.验证码_Drawing_
{
    /// <summary>
    /// 生成验证码的类
    /// </summary>
    public class ValidateCode
    {
        public ValidateCode()
        {
        }
        /// <summary>
        /// 验证码的最大长度
        /// </summary>
        public int MaxLength
        {
            get { return 10; }
        }
        /// <summary>
        /// 验证码的最小长度
        /// </summary>
        public int MinLength
        {
            get { return 1; }
        }
        /// <summary>
        /// 生成验证码
        /// </summary>
        /// <param name="length">指定验证码的长度</param>
        /// <returns></returns>
        public string CreateValidateCode(int length)
        {
            int[] randMembers = new int[length];
            int[] validateNums = new int[length];
            string validateNumberStr = "";
            //生成起始序列值
            int seekSeek = unchecked((int)DateTime.Now.Ticks);
            Random seekRand = new Random(seekSeek);
            int beginSeek = (int)seekRand.Next(0, Int32.MaxValue - length * 10000);
            int[] seeks = new int[length];
            for (int i = 0; i < length; i++)
            {
                beginSeek += 10000;
                seeks[i] = beginSeek;
            }
            //生成随机数字
            for (int i = 0; i < length; i++)
            {
                Random rand = new Random(seeks[i]);
                int pownum = 1 * (int)Math.Pow(10, length);
                randMembers[i] = rand.Next(pownum, Int32.MaxValue);
            }
            //抽取随机数字
            for (int i = 0; i < length; i++)
            {
                string numStr = randMembers[i].ToString();
                int numLength = numStr.Length;
                Random rand = new Random();
                int numPosition = rand.Next(0, numLength - 1);
                validateNums[i] = Int32.Parse(numStr.Substring(numPosition, 1));
            }
            //生成验证码
            for (int i = 0; i < length; i++)
            {
                validateNumberStr += validateNums[i].ToString();
            }
            return validateNumberStr;
        }
        /// <summary>
        /// 创建验证码的图片
        /// </summary>
        /// <param name="containsPage">要输出到的page对象</param>
        /// <param name="validateNum">验证码</param>
        public byte[] CreateValidateGraphic(string validateCode)
        {
            Bitmap image = new Bitmap((int)Math.Ceiling(validateCode.Length * 12.0), 22);
            Graphics g = Graphics.FromImage(image);
            try
            {
                //生成随机生成器
                Random random = new Random();
                //清空图片背景色
                g.Clear(Color.White);
                //画图片的干扰线
                for (int i = 0; i < 25; i++)
                {
                    int x1 = random.Next(image.Width);
                    int x2 = random.Next(image.Width);
                    int y1 = random.Next(image.Height);
                    int y2 = random.Next(image.Height);
                    g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);
                }
                Font font = new Font("Arial", 12, (FontStyle.Bold | FontStyle.Italic));
                LinearGradientBrush brush = new LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height),
                 Color.Blue, Color.DarkRed, 1.2f, true);
                g.DrawString(validateCode, font, brush, 3, 2);
                //画图片的前景干扰点
                for (int i = 0; i < 100; i++)
                {
                    int x = random.Next(image.Width);
                    int y = random.Next(image.Height);
                    image.SetPixel(x, y, Color.FromArgb(random.Next()));
                }
                //画图片的边框线
                g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
                //保存图片数据
                MemoryStream stream = new MemoryStream();
                image.Save(stream, ImageFormat.Jpeg);
                //输出图片流
                return stream.ToArray();
            }
            finally
            {
                g.Dispose();
                image.Dispose();
            }
        }
        /// <summary>
        /// 得到验证码图片的长度
        /// </summary>
        /// <param name="validateNumLength">验证码的长度</param>
        /// <returns></returns>
        public static int GetImageWidth(int validateNumLength)
        {
            return (int)(validateNumLength * 12.0);
        }
        /// <summary>
        /// 得到验证码的高度
        /// </summary>
        /// <returns></returns>
        public static double GetImageHeight()
        {
            return 22.5;
        }
    }
}


//2. 在Controller.cs中，添加Action，用来设置将生成的验证码存入Session，并输出验证码图片

//[AllowAnonymous]
//public ActionResult GetValidateCode()
//{
//ValidateCode vCode = new ValidateCode();
//string code = vCode.CreateValidateCode(4);
//Session["ValidateCode"] = code;
//byte[] bytes = vCode.CreateValidateGraphic(code);
//    return File(bytes, @"image/jpeg");
//}

//3. 调用方式为：在需要使用验证码的页面中，加入<img> 标签：

//<img id = "valiCode" style="cursor: pointer;" class="col-md-2 control-label" src="~/Account/GetValidateCode" alt="验证码" />


//4 验证码匹配
//[HttpPost]
//[AllowAnonymous]
//[ValidateAntiForgeryToken]
//public async Task<ActionResult> Login(LoginViewModel model, string returnUrl)
//{
//if (model.ValidCode != Session["ValidateCode"].ToString())
//{
//ModelState.AddModelError("", "验证码不正确.");
//return View(model);
//}


//if (ModelState.IsValid)
//{
//var user = await UserManager.FindAsync(model.UserName, model.Password);
//    if (user != null)
//{
//    await SignInAsync(user, model.RememberMe);
//    return RedirectToLocal(returnUrl);
//}
//else
//{
//    ModelState.AddModelError("", "Invalid username or password.");
//}
//}

//// 如果我们进行到这一步时某个地方出错，则重新显示表单

//return View(model);
//}

//5. 点击图片刷新验证码
//@section Scripts
//{
//@Scripts.Render("~/bundles/jqueryval")

//<script type="text/javascript">
//             $(function () {
//    $("#valiCode").bind("click", function() {
//        this.src = "../Account/GetValidateCode?time=" + (new Date()).getTime();
//    });
//});
//</script>

//}

//参考博文：http://www.cnblogs.com/LetsLazy/p/3938801.html